Stretch-bending machine



July 19, 1949. P. F. MAlzE STRETCH-BENDING MACHINE 4 Sheets-Sheet 1 Filed lApril 14, 1945 wam, f

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' July 19, i949. pL F.' MAIZE 2,476,556

STRETCH-BENDING MACHINE,

Filed April 14, 1945 4 SheetS-Shet 2 E .4. y 'www `luly 19, 1949. P. F. MAlzE 2,475,556

' STRETCH-BENDING MACHINE Filed April 14, 1945 4 sheets-sheet s l 1N V EN TOR. 72H2 FMQZ'Z?, BY

July 19, 19449. g P. F. MAlzE 2,475,556

` STRETCH-BENDING MACHINE Filed April 14, 1945 v 4 Sheets-Sheet 4 Patented July 19, 1949 ere'rreH-.BE'NDING lfqol F. Maize, Detroit, Mich., assignor to ABriggs Manufacturing Company, Detroit, Mich., 'al cor# poravttion of Michigii i springer/ign ppn 14 1945.3 serial N9. 588,324 inknngs. (c1. 15s-4s) A further object'of the-'invent nis to bend or form in improved 'mnner by'"e;` bending ind stretching operati@ e metal SGfp of angular cross-section into longitudinally irregular'eom tour'in which l23,11 bent'port ns of the strip, after te operation has 'been ggnpre'c, i@ not 11e in@ Single pljee- More speoioellyen .object of vthe invention lis to bend an elongate metal S'trip'over .Shaped die'whn'a'tithe s@ strip and causing it tocof configuration or CQrlfO-.llf-Qf. y f Y in said dief' f Still another object. .of the im? ritieni-S te nro.- .ide a.mechenismfor.-loerrdge e. Vdie and s iin'ul'ta'neouslyvr rtlng t" Asion on the strip todrawor 'forceitfint t 'efchnnelf the 11k@ of irregui' Ongi parmi configuration if; Athe die .thereloy'ioer .neilllylralhefhestrip the Contour ofthe (ond also to .the'leheitdl .ooneuraton'of .theleiov'or .oheinnel #further/object o f the n t'ionto provide e. reletiuelylco pai` t'," easily leegnd eflicie t me'ohanismrfo'r eoloorriplishineihe foreeone'pi tal strip .over

poses,v and in particular to provide e construe on f .end Aeinem.gemelli 0f Athe operating mech by WhiGh the overall lengt." 'f .the'maohne and .the space occupied by .the no hine' rriagy be mete; -iau'y reduced;' 'Y' 'Omer gbjeS-@ this ilnYentiOn v,Will appear Y,ilo the' 'following' ideeeripon rid olonne, ,reere Joenehad totheaecomo me drewirigsiorm .fa part ,of nos specimen nihereinlkje reference .ohereorere oesieoefeleorresr. ine' leere: 1o i ne .several views.

epeoi'ire .new .ore ne apparatus eerie "lfibledinleni 0? :thepresent invention.

.-Fig. 2- is Lle.fr.agmentory perspeetiveifew look.-

ini-ig.

Eig. 6 is a diagremniatic View showing the pne mattie circuit by which the Work clamps are in eccoli; t nyin'g tirewirlgs,A since the' 'inierf-` bien 1S eepebl of other embodiments. en@ of herrie practiced or, celrriedout inV various Ways. 'Alsj it is to bennderstoodthat the phralseology' or' terminology employed herein is for the purpose of dsoripnonsndnq ofumitatign.

the dowiriee there iis illus'troted, by .wey 0f example, one e'ibodinient of the present in vexif-- tihon in the f orr'n of bending or forming fn lonigitemetal stripgarl'i evieri'fl oroos-.Seotioo t.. theidesired'oontour, the ooristriiotfqrl and Op 'beingllh .that th.. strip Wi be bent in i gth in more than directions 'as determined Eby' the lbneitudnalcoj figuration ofi efgfo .e richfannel in the die, thereby Permenerrt'li" o ming portions of the Strip. So. 21o-.S to lie in diierent plneSl' The illustrated I ngi'f' chine comprises 'an upright frame Il! upon which ifs'suppor'td .horizontal bed f H; The ironie pref'ere y e ornpr, esy vlaterally spaced Vertic'ei side mi'i Yers'l a;n `l villb' .providing a spegc'e therelqetwen for rieopergting mechanism es hereinater described'. Mounted upon the hed and ia justa-bieIiqgitudmany thereon are a pair.

of cr' blocks i?,V mglA I3 which rigidly support a forming and 'streehirle die I4 .having the pio'er Surface' 'thereof crowned or otherwise curved in c'cordance yWith"`the desiijecllcontour to be pertedto e metalstripor Y'elollgzite Workpiecefl'. In't'he present instance, as shown in Fig. 4, the metal strip A.l5 .tlbehent or formed is angular in ci'fosgi-seotion'.'4 Ho; i)veyer';y it Will` be understoodI tht" thep'arti larcrosssectional shape of the Wokpieceiney ery from that herein illustrated'. "las 'iiiusreiteol paricpisriygp Figs. .3 and 4, rifle metalistrip J5 'isidre'ufn inton and formed within groei/eer ,channel l'c'ut intheupper surface of the' forming 'fili nd extending frorn end 'to end thereof.V `I l'ns.f grooie orche'nnel in the prese 'enternbo'diment Lof 'the invention, illustrated,` wey df examplegisshown as sinuous or serpentine in'sh'ape. ,In otherfwo'rds',.the forming groov c dI lennk'e;1 l'fhasn irregulerlongitudinel congi liretir. .litri '.rierr'oorollel Sides; and es o' @meer .iiier'lo ihe'istrilo lorinorkpiece le, when drawn dow'nor stretched oyerthe upper surface ci the die and .forced i vtothis groove or channel', Will helve en irreg'uiei lQngtudinel conguratio. .will .be eeen," the werkbieoe or ,strip will betloeirt the forx'ningdiefin three or more directions to "redfoontolrr orshooefof three .or more di.'- "re. The forming channelfor 3 or tapering sides and is shaped so as to receive and conform to the cross-sectional shape of the strip I5. Although not necessarily so, the depth of the channel is preferably at least as great as the height of the workpiece when positioned as shown.

Mounted upon the bed II beyond Aone end of the forming die I4 is a clamp supporting block I1 which is adjustable longitudinally of the bed and adapted to be rigidly bolted thereto in proper position. Above the block I1 is an inclined platform I8 pivoted at I9 to the outer end of the block and supported in the desired angular position by means of one or more adjusting screws which may be adjusted vertically to vary the tilt of the platform. Mounted in xed position on the platform I8 is a clamp 2| carrying a series of four jaw members 2Ia shaped in common to receive one end of the workpiece I5. These jaws are slidable in one direction or the other in the usual manner along inclined interior surfaces of the clamp 2I so Yas to clamp or release the workpiece and are carried by a shiftable holder 2lb secured to a piston rod 22 (see Fig. 6) which in turn isV secured to a piston 23 slidable within an air cylinder 24.

The clamp 2| with` its clamping or gripping jaws 2 Ia, above described, provides a fixed means for clamping and holding one end of the workpiece I5 during the bending or forming operation. The opposite end of the workpiece is adapted to be rigidly clamped by means of a clamping device 25 carrying clamping or gripping jaws similar to the clamping device 2 I. The jaws of the clamping device 25 are shiftable longitudinally in order to grip or release the Work by means of a holder 25a secured to a piston rod 26 which in turnris connected to a piston 21 shiftable within an air cylinder 28. This cylinder is pivoted at its outer end at 28a to a bracket 29 rigidly mounted on a platform 30. The platform 3E together with the clamping device 25 secured thereto extends between the spaced upright sides 3I of a bifurcated block, and the clamp 25 is pivoted or trunnioned in the upper ends of this block at 32. By this construction the clamping device 25 as well as the platform 30 and parts mounted thereon are adapted to pivot or swing about a horizontal axis formed by the pivots or trunnons 32.

The bifurcated block 3|, which pivotally supports the work clamp 25 and its pneumatically operating mechanism, is rigidly secured to the upwardly projecting arm .of a bell crank lever 33 which is fulcrumed or trunnioned intermediate its ends at 34 on the upright side portions Illa and |027 of the supporting frame I 0. The lower arm 33a of this lever lies between the `frame members Illa and IIIb below the bed of the machine and is pivotally connected at 35a to a clevis 35 secured to the outer end of a piston rod 36 connected to a piston 31 (see Fig. 5) slidable within a hydraulic cylinder 38. The cylinder 38, as shown in Fig. 2, is pivotally mounted by means of trunnions at 39 on the upright sides of the frame I0, this construction permitting the hydraulic cylinder 33 to swing Vabout a horizontal axis during the bending operation.

The mechanism by which the work clamp devices 2I and 25 are pneumatically operated is illustrated diagrammatically in Fig. 6. Mounted on the floor or supporting base for the machine and arranged side byside are a pair of conventional four-way air Valves 40 and 40a. Since the piston and cylinder mechanism for each of the clamp devices is controlled in the same manner, a description of the circuit for one thereof will suice for both. Air under pressure from a suitable source of supply is introduced into each valve 40 and 40a through pipes 4I communicating with a main air inlet supply pipe or conduit 42.

' A pipe line 43 extends from each valve to the outer end of the clylinder '28 or 24 at a point behind the piston therein. A second pipe line 44 extends from the valve and communicates with the opposite end of the cylinder. Also extending from each valve is an air exhaust pipe 45. Each valve is operated by means of a pair of foot pedals 46 and 41. When the pedal 46 is depressed air under pressure entering the valve through pipe 4I will be diverted through pipe 43 into the outer end of the cylinder thereby forcing the piston inwardly to release the clamp. Air will be exhausted during this movement of the piston through' pipe 44 and thence through the valve to the atmosphere through pipe 45. TheV reverse operation will take place when the pedal v41 is depressed to cause air under pressure to ow throughline 44 into the inner end of the cylinder thereby forcing the piston outwardly to operate the work clamp and, hence, clamp the end of the strip I5.

The mechanism for controlling the hydraulic cylinder ,and piston mechanism 31, 38, which in turn operates the bell crank lever 33, is illustrated more particularly in Fig. 5. Oil or other hydraulic medium contained within a 'supply tank 48 is drawn from the tank through pipe 49 by a hydraulic pump 50 of conventional construction driven from an electric motor 5I. rIhe pump delivers iuid under pressure through pipe 52 to a suitable pressure control valve 53 provided with an adjusting screw 54 which may be adjusted to give the desired pressure setting as indicated by the reading on a pressure gauge 55. Oil under pressure corresponding to the setting made by the pressure control adjusting screw 54 is delivered from the valve 53 through pipe 56 to a four Way spring control valve 51 of conventional type, this valve being operated manually .by a control handle 58 so as toY control the direction of flow of the hydraulic medium into and out of the valve in accordance with the direction in which the piston .31 is to be shifted within the cylinder 38.

Communicating with the valve 51 is a pipe line 59 which is connected to a pipe or conduit 60 leading to a one-way check valve 6I which is adapted to open when theV pressure is in the direction of the arrows and permit the fluid to flow through thecheck valve. VThe pipe 59 is extended at B2 to communicate with a needle valve B3 controlled by means of an adjusting handle 63a. Fluid under pressure passing through the check valve 6I ows through a pipe 64 into pipe line 65 communicating with the needle valve 63 andalso with the cylinder 38 at the head side of the Vpiston, 31. Thus when the fluid under pressure enters the cylinder through line 65 it will force the piston 31 outwardly. During this operation iluid will be exhausted from the opposite end of the cylinder through a pipe lineBS communicating with a check valve 61 and also with aY pipe 68 leading to a one-way volume control valve 69 of conventional construction. Fluid exhausted from the cylinder through pipe |56V is blocked by the check valve 61 and, hence,

flows through pipe 68 into the valve 69 and is metered therebyin order to control the speed of the stroke of piston 31. The valve ES'may be adjusted or set in order to. vary the volume or liquid adapted to flow through the valve from pipe 68 by means off an adjusting handle 1|), the proper setting being indicated by the reading on the dial of the valve. Thus, any desired speed of travel of the piston 31 may be obtained by properly adjusting or setting the volume control valve E9 through handle 10. From this valve'the fluid is returned through pipe line 1 I to the fourway valve 5i. VThe pipe 66 communicates through check valve 61 with a'by-pass pipe or conduit 12 leading into the pipe line 1|. With the four-way valve 51 set so that huid under pressure will ow in the direction of the arrows, thereby forcing the pistonl 31 outwardly, the return flow of iluid through line 1I will pass through the valve 51 and thence through return line 13 into the supply 'tank 48.

It will be readily understood from the foregoing and from a consideration of Fig. 5 that return travel `of the piston 31 in the opposite direction will vbe achieved by manipulating the handle 58 to set the four-way valve 51 so as to cause fluid from the pump to be deliveredV from line 56 into pipe line 1I. When the iiow is in this direction the fluid will be blocked at valve ligand, hence, will ow through pipe 12, opening check-valve 61, and thence will. iiow through line 6'6 into the outer end of the cylinder 3B. As the piston isvretracted' fluid will be exhausted from the opposite end of the cyli-nder through line B5 past needle valve 63 into Ipipe 't2 and thence through pipe 59 to the fourwa'y valve 51, passing out of this valve through exhaust line 135. The pressure of the iiuid passing through line vt5 opposite to the direction of -the arrows will close the check valve 5|. The 'speed 'of the return stroke of the piston 31 will be governed by the setting of the needle valve '63 and the restriction offered thereby to the iiiow of iiuid from line `65 past the needle valve into-1in@ e2, Y

From the foregoing it will 'be l"seen that outward motion of the piston 31 and piston rod -36 will swing the bell crank lever 33 about its ful- 1 lcru-rn at 34 thereby swinging the upper arm of the bell v'crank and the carrier block 3-I outwardly for away fromy the lend of the 'forming die SI4. -Since one end off the workpiece I5 is rigidly secured in 'the cla-mp 425 carried by block 3|, and fs'ince the opposite fend of the workpiece is held in xed position by the clamp 2|, outward vswinging motion of the upper end of the bell crank 33 will place the workpiece or strip in tension and exert a stretching 'action Ithereon.

.In using the machine herein illustrated as exemplifying one embodiment of the invention the bar or strip I5, which may be of any suitable metallic material, Vsuch as aluminum alloy, is lir'st bent or preformed to the approximate shape 'of the die so that it may Ibe placed 'over Athe upper surface of the die I4 with the ends bent down sufliciently so as Ito .permit them )to be inserted into the jaws fof the 4clamps 2| and T25. These jaws at this time will have been opened by operation of the pneumatic mechanism through depression of .pedals '46 as previously 'described land particularly shown lin Fig. =6. After 'the ends Vof the strip or workpiece I5 'have been inserte'd yinto the .clamps the operator depresses 6, will 'overlie' eitherone orthe other or vboth of the inclined or tapered sides of the forming groove or channel I6. With the strip properly positioned and clamped at opposite ends the cons trol handle 58 is manipulated to shift the mech, anism of four-,way valve 51 from neutral to a pot sition in which the hydraulic medium from the pump` 50 isV forced through the valve into pipe line 59V. With the ow in the direction of the arrows in Fig. 5 the piston 31 will be forced outwardly in cylinder v38 thus swinging 4the bell crank lever 33 and shifting the block 3| away from the end of the die I4. The rate of travel of the block as wel1 as the clamp 25 willbe gov. erned as. desired -by adjusting the volume control valve 69. The distance that the clamp trav., els and, hence, the extent to which the work strip is stretchedV may be ascertained by reference to theA reading given by a fixed pointer 15 on a scale carried by the block 3|.

As .the clamp 25 moves away from the end of the die it travels outwardly and downwardly in an arcuate path centered at the pivot 34v of the bell crank. As this operation proceeds the work strip I5 is progressively stretched and at the same time drawn downwardly into the forming channel I6. This operation is possible by reason o f the fact that the apex of the angle piece engages one'or the other sloping side of the channel and slides or is cammed down into the bottom of the channel as the work strip is drawn down over the die. The combined stretching and bending operation draws the strip uniformly into the ir,- lregularly shaped channel and causes it to persrnanently assume a conliguration corresponding to the longitudinal conguration of the channel. Upon completion of the operation the pcd.- als 46' are depressed to release or open the clamps 2 I; 25 and permit withdrawal of the finished strip. Thereafter the hydraulic mechanism will beep.- ;erated to return the bell crank lever to its startingposition. Y

It will be noted that the construction and ar- -rangement'of the operating mechanism ror shifting the 'clamping device 25 during the stretch- 'ben-ding operation are such as to enable substantial portions of this mechanism to be positioned below the clamping device 25 and housed iin the 'space between the upright frame mem.

bers Ilia and 'Ib, thus providing a very compact construction in which the space occupied by the machineris rreduced Ato a minimum. In the pre- 'ferred construction, therefore, the bell crank lever 33 is pivotallywmounted at 84 below the clamping device :25 and toward the center of the machine `as `seen in Fig. 1. By extending the arm 33u of the lever downwardly, as shown iin dotted lines jin Fig. .1, the hydraulic cylinder 38 Sand its pivotal connection vat 35a with the lever arm 33a may alsobe positioned below the clamp- ?i-ng device and toward lthe center of the mach-ine, ithus enabling maximum .utilization of the space llbelow the bed |i| and considerably reducing the overall length of the machine.

-I claim:

1. iIn -a bending machine, a forming die having an upwardly `facing forming groove, a clamping device supported at one end of said die and vhav- *iing jaws movable -to grip or release one end of a Vmetal strip to be stretched in said groove, huid actuated lmeans for moving said jaws, a second clamping device at ithe opposite end of said die and having jaws movable to grip or release the opposite end of the strip, iiuid actuated means for moving said last named jaws, supporting' means 4for said second clamping'd'evice and last named fluid actuated means, a swinging member pivotally mounted intermediate its ends and having an articulated connection at its upper end with said supporting means, land uid actuated YIneans pivotally connected to the lower end of said member for swinging said member to move said second clamping device relatively to the rst clamping device to stretch said strip; the pivotal mounting of said swinging member, said last named fluid actuated means andrits pivotal connection, each being positioned below said second clamping device and toward the center of the machine.

2. In a bending machine, a forming die having an upwardly facing forming groove, a clamping device supported at one end of said die and having jaws movable to grip or release one end of a metal'strip to be stretched in said groove, iluid actuated means for moving said jaws, a second clamping device at the opposite end of said die and having jaws movable to grip or release the opposite end of the strip, fluid actuated means 4for moving said last named jaws, supporting means for said second clamping device and last named fluid actuated means including a swinging bell crank lever pivotally mounted intermediate its ends and to the upper end of which said supporting means is pivoted, and means pivotally 'connected to said lever for swinging the lower end of said lever in one direction to move said second clamping device in the opposite direction and thereby stretch said strip, the pivotal mounting of said bell crank lever, said last named means and its pivotal connection with said lever, each being positioned below said second clamping device and toward the center of the machine.

3. In a bending machine, a forming die having an upwardly facing forming track to receive a metal strip to be bent, a clamping device at one ,end of said track and having jaws movable to grip and release one end of the strip, fluid actuated :means for moving said jaws, a second clamping device at the opposite end of the track and having jaws movable to grip and release the opposite end of the strip, fluid actuated means for moving said last named jaws, a swinging lever pivotally Amounted intermediate its ends, a support for said second clamping device and said last named uid `actuated means pivotally mounted on the upper end of said lever, and uid actuated means pivotally connected to the lower end of said lever for swinging said end in one direction thereby -to move said second clamping device in the opposite direction relatively to the rst clamping device; the pivotal mounting of said lever, said Ilast named uid actuated means and its pivotal connection, each being positioned below said second clamping device and toward the center of the machine.

4. In a bending machine, a forming die having an upwardly facing forming track to receive a metal strip to be bent, a clamping device at one end of said track and having jaws movable to grip and release one end of the strip, a tiltable vertically adjustable support for said device, fluid ac- Z-tuated means for moving said jaws, a second clamping device at the opposite end of the track and having jaws movable to grip and release the opposite end of the strip, fluid actuated means for vmoving said last named jaws, a swinging lever pivotally mounted intermediate its ends,a support for said second clamping device pivotally mounted on one end of said lever, and fluid actuated means pivotally connected to the opposite end of said lever for swinging said end in one direction thereby to move said second clamping device in the opposite direction relatively to the rst clamping device; the pivotal mounting of said lever, said last named fluid actuated means and its pivotal connection, each being positioned below said second clamping device and toward the center of the machine.

5. In a bending machine, a vertically arranged forming die having an upwardly facing forming surface to receive a metal strip to be bent and stretched, a pair of clamping devices at opposite ends of the die, leach device having movable jaws adapted to grip and release one end of the strip, means for operating the jaws of each clamping device, a swinging bell crank lever pivotally mounted intermediate its ends, a support for one of the clamping devices and its jaw operating means pivotally connected to the upper end of said lever, and means connected to the lower end of the lever for swinging the same to move said last mentioned clamping device relatively to the othericlamping device; the pivotal mounting of said lever, said last named means and its connection to the lever, each being positioned below said last mentioned clamping device and toward the center of the machine.

6. In a bending machine, a vertically arranged forming die having an upwardly facing forming surface to receive a metal strip to be bent and stretched, a pair of clamping devices at opposite ends of the die, each device having movable jaws adapted to grip and release one end of the strip, means for operating the jaws of each clamping device, a swinging bell crank lever pivotally mounted intermediate its ends, a support for one of the clamping devices and its jaw operating means pivotally connected to the upper end of said lever, a vertically adjustable support for the other clamping device and its jaw operating means, and means connected to the lower end of the lever for swinging the same to move said first named support and the clamping device carried thereby relatively to the other clamping device; the pivotal mounting of said lever, said last named means and its connection to the lever, each being positioned below said last mentioned clamping device and toward the center of the machine.

PAUL F. MAIZE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 537,550 Schacht Apr. 16, 1895 1,710,261 Kellogg Apr. 23, 1929 2,218,503 Brooks et a1 Oct. 22, 1940 1 2,255,867 Wisckol Sept. 16, 1941 2,269,549 Oeckl Jan. 13, 1942 2,292,731 Amiot Aug. 11, 1942 2,305,850 Drysdale Dec. 22, 1942 2,357,027 Seifried Aug. 29, 1944 2,371,587 Seifried Mar. 13, 1945 2,378,413 Lermont et al. June 19, 1945 2,431,173 HawkesV Nov. 18, 1947 

